Results of two experiments, one greenhouse project and one field study, indicate that high heavy metal concentrations in smelter-contaminated soils and in tree seedlings grown thereon, increase mortality rates. Factors that increased survival and growth of trees were: (i) liming the acidic, polluted soils, and (ii) using containerized seedlings. Both methods reduced the toxic potential of heavy metals in the plant and soil systems. Species were significantly different in their respective rates of survival and growth. These differences were due primarily to inherent growth habits and tolerances to adverse growing conditions.
Field study results indicate that differences in overall survival of tree seedlings was a function of soil type (site).
Findings suggest that the major cause of plant mortality, as. modified by site, was high concentrations of Zn in seedling tissue and in soils.